very heavy and slow focusing
you have to manually retract the lens at times...pain in the neck but worth the trouble as I wouldn't want to store it with the lens not retracted...seems like it would foul up the USM motor

This and the 300/2.8is are the two top lenses in my bag bar none.
Incredible detail with great focusing patience on the part of the shooter.
A heavy but unassuming lens...this is among Canons very best lenses.

color is natural...probably good for most uses, but I would like a little more warmth in it.

Sharper than the 70-200 faster lenses...I agree with the ratings putting this lens a "few" percentage points above the 2.8 and the 2.8IS.

Smallish and light...an easy carry hand held where the 2.8 and the 2.8IS are somewhat heavy and require a larger bag.
I carry 2 cameras...the 24-70 on one and the 70-200/4 on the other in a very small casual bag.
Fabulous combination.

Very heavy for a so-called "walk around" lens...The Tamron 28-75 fits this scenario much better

I'm normally Prime all the way...hated zooms...but this zoom is almost as good as a prime in color and detail...
The Reb

Update: A friend, whose advice I respect, advised me to get the Tamron 28-75/2.8....I did...it was sharper and the color/contrast better than the Canon 24-70. I sold the 24-70 and paid for the Tamron 28-70 and bought a Canon 135/2 with the remainder....forget the 24-70...waste of cash IMO.